Production of color photographic images



Patented May 22, 1945 PRODUCTION OF COLOR PHOTOGRAPH) IMAGES Wilhelm Schneider and Alfred Frohlich, Dessau, and Gustav Neugebauer, Bitterfcld, Germany; vested in the Alien Property Custodian No Drawing. Application April 11, 1942, Serial No. 438,566. In Germany October 22, 1940 Claims.

with a special agent as, for instance, another dyestuff former. There have also been used silver halide emulsions which from the start contain the image dyestuffs. In this case the dyestuils are removed at the places containing silver to form the color image as, for instance, by the silver dyestufl bleaching out process. Since in this process colored layers are employed, the photographic material cannot of course serve for exposure, but it is practically suited'only as a copying material. This disadvantage exists with all methods in which colored layers are used. In order to overcome this disadvantage it has already been proposed to use silver halide emulsion layers having dyestuff formers for the silver dyestuf'f bleaching out process and to form the dyestuffs in the layers after exposure or development and then to destroy the dyestuffs corresponding to the images according to the silver dyestufl bleaching out process. The method is of course disadvantageous inasmuch as the dyestufl must at first uniformly be produced in each layer and then be destroyed corresponding to the component silver images in one operation Furthermore there is a method in which the- -silver image is directly converted into an azo dyestuff image. In this case by the treatment with diazo solutions the silver image is transformed into a silver antidiazotate image which then forms dyestuif images with the azo coupling components already contained in the layers.

Moreover it has already been suggested to transform the silver image into an azo dyestuff image in such a manner, that the silver image is I converted into a soluble nitrite compound and azo dyestuffs are formed by this nitrite compound from azo coupling components which were ble azo dyestuff components to the gelatin emulsion i to be performed in such a way, that these water-insoluble components are precipitated from a solution in the gelatin. However, it has always present in a water-insoluble condition in the 511- Y ver halide emulsion. The addition of the insolubeen observed that silver halide emulsion layers with such dyestufl formers precipitated in the elatin are not suitable for the production of colored images since these precipitated dyestufl 5 formers exhibit too low a reactivity and the transparency of the dyestuil images and hence the capability thereof of being projected and enlarged are considerably reduced by these dyestufi' form'- era In accordance with the invention we have found that the above mentioned drawbacks of. the methods hitherto known can be avoided in the photographic production of azo dyestufl images by producing an azo dyestuii insilver halide emulsions by azo dyestufi coupling from a'diazotizable amine and a compound capable of azo coupling, at least one of these reactants already being in a non-diffusing form in the layer, at the places free from silver after development of the silver image and, if necessary, after fixing and then removing the image silver and, if necessary, the residual silver salts in a manner known per se. It is surprising, that an azo dyestufl is formed at the points free from silver in a photographic layer,-which contains an amine capable of being diazotized besides a silver image, after the treatmerit of the layer with a hydrochloric acid-nitrite solution and the solution of an azo coupling component not containing a salt of a heavy metal or any other additional compound. The course of this reaction is also complete when the photographic layers already contain an azo coupler in a condition fast to diffusion, for instance, a derivative of naphthol or of pyrazolone in which case it is immaterial whether or not the nitrite solution contains a salt of a heavy metal.

The following example illustrates the modification:

A silver halide emulsion layer containing a-hydroxy-p-naphthoyl-2-amino-3-palmityl amino toluidine-5-sulfonic acid as the azo coupler is exposed by means of a gray wedge. After dc velopment of the silver image and fixing the layer is bathed in a 1% solution of dehydrothiotoluidine-4-sulfonic acid for 20 minutes, washed, then treated with a solution consisting of 8 cc. of 1/1 normal sodium 'nitrite solution and 1000 cc. of 1/25 normal hydrochloric acid, subsequently washed again for a short time, and finally treated in a l 1 normal sodium acetate solution. A red dyestuff is produced thereby in the layer at the places free from silver and a reverse dyestufi image of the original silver image is obtained after the removal 0! the silver either with a solu- 55 tion of potassium cyanide or with Farmer's reboth sides of the support.

ducerp Since the ,diazotizing solution does not notably influence the non-diffusing azo coupling components being in the layer, for instance, naph thols or compounds having reactive methylene group such as pyrazolones, it is possible to use for this process silver halide emulsion layers already containing azo couplers. be applied to single layers as well as a multi-layer material. In the latter case several silver halide emulsion layers, which contain different azo dyestuif couplers and exhibit different spectral sensitivities to light, are arranged in superposition, if necessary together with filter layers on one or:

Such material is suited to the exposure as well as the reproduction of multi-color images.

We have moreover found that also non-diffusing amines which are contained in the silver halide emulsion layers already before exposure can unobjectionably be diazotized also in the presence of azo coupling components. This modification is illustrated by the following two examples: (a) 2 g. of the 'urea with the formula carbonyl-di- (p-aminobenzoyl-p-phenylene-diaminosulfonic acid) are dissolved in 80 cc. of water. The solution is mixed with a solution of 3 g. of sodium a-hydroxy-,6-naphthoyl-2-amino-3-palmityl-amino-toluidine-5-sulfonate in 30 cc. of water. The mixture is cooled to 15 C., filtered and added to 300 cc. of a silver halide emulsion. The layer cast therefrom is exposed, developed, and fixed whereupon it is treated in a nitrite solution having the composition described in the above-mentioned example. After a short washing the layer is brought into a 1/1 normal sodium acetate solution whereby the dyestufl coupling is effected. After the removal of the silver with a usual bleaching bath or a potassium cyanide solution one obtains a red dyestuil image which represents a reverse image of the silver image as first formed. If an acetic acid solution is used for the diazotization instead of the hydrochloric acid solution, the dyestuff coupling is already effected in the diazotizing bath.

(b) 3 g. of sodium a-hydroxy-p-naphthoyl- Z-amin'o-3-palmityl-amino-toluidine-5-sulfonate are dissolved in 40 cc. of water and a solution of sodium 4-methyl-octadecyl-amino-aniline-3- j sulfonate in 20 cc. of methanol and 40. cc. of 1 water is added thereto. The whole is mixed with 1 300 cc. of a silver halide emulsion and then ca t to form a layer.

and fixing the layer is bathed in a solution con-- i sisting of 8 cc. of 1/1 normal sodium nitrite 1 solution, 1000 cc. of 1/25 normal hydrochloric f acid and 10 cc. of 5% copper chloride solution 1 for 3 minutes. After watering the layer is treated 1 in a 1/1 normal sodium acetate solution whereby j a red azo dyestuff is formed at the places free 1 from image. 1 image one obtains a reverse dyestuif image of the silver image. pling bath may be omitted if acetic acid is sub- 1 stituted for the hydrochloric acid in the diazotizing bath since in this case the coupling is al- After exposure, development After the removal of the silver The acetate bath as the couready effected in the diazotizing bath. The

5 gradation of the dyestuif image may essentially be influenced by varying the concentration of the salt of the heavy metal in the diazotizing solution.

The process of the present invention substanstart be incorporated in the layers. In the known processes'for instance, the antidiazotate' three partial color images'are produced from the The process can.

different dyestuff formers contained in the layers by reacting them with another dyestuff former not being in the layers, for instance, antidiazotate in which case the coupling bath may simultaneously ,be used for removing the silver image by adding a silver dissolving agent, for instance, potassium cyanide or a bleaching and fixing'agent. such as Farmers reducer to the bath. In the process hitherto known it is therefore necessary to adjust the dyestuff formers added to the layers and, the dyestuif former not contained in the multi-layer material in such a manner that solely by the latter dyestuff former a different dyestuff image is produced in each emulsion layer viz. a yellow, purple and blue-green partial color image in the correct color tones. It is to be understood that under these conditions the selec-,

,tion among the known dyestuff formers is very limited. for .it is known to be very difflcult to produce three dyestuffs, yellow, purple and bluegreen with a single diazo'compound and three different coupling components which must moreover satisfy certain photographic conditions.

In contrast with these methods both dyestufi formers can be added to the silver halide emulsion layers in the present process, 1. e., the azo component as well as the diazo component, the latter in the form of an amine capable of undergoing the diazo reaction. Thus it is possible to construct the desired dyestuif in each layer of the multi-layer material from components which yield not only the desired color but the most favorable tint.

According to the antidiazotate process hitherto known it was necessary, for instance, to produce the three partial-color imagea'for instance, with tetrazotized dianisidine as the general diazo component and with di-(acetoacetyl)-benzidine for the yellow image, with di-(2,3-hydroxynaphthoyl) -dianisidine for the purple image and with steryl-H-acid for the blue image, the azo components being incorporated in the single layers. By the present invention, however, each dyestuff is formed in the single layers from different azo components and different diazo components as, for instance, the yellow dyestuff from 1-phenyl-3-heptadecyl-5-pyrazolone- 3-sulfonic acid and the tetrazotized urea obtained with two mols of sodium p-aminobenzoyl-p-phenylene-diamine-sulfonate, the purple dyestuff' from di-(2.3-hydroxynaphthoyl) -benzidine and the tetrazotized urea obtained with two mols of sodium p-aminobenzoyl-p-phenylenedia mine sulfonate and the blue-green dyestuif from the tetrazotized octylether of dihydroxybenzidine and 8 stearyl amino-naphthol -2.4 -disulfonic acid. This possibility of adding a diazo component as well as a coupling component to each layer represents a considerable advantage over the possibilities hitherto known, for it is nearly impossibleto construct the three dyestuffs yellow, purple and blue-green from one diazo component and three different coupling components in such a maner that satisfactory partial color images are obtained. All these dyestuff formers mentioned above which are fast to diffusion are incorporated into the photographic multi-layer material already in the production thereof. It is of advancasting in the form of an aqueous, if necessary, alkaline solution which may contain an organic solvent, if necessary.

For the production of a multi-layer material the silver halide emulsion layers containing the amines capable of being diazotized and the azo coupling compounds are sensitized to different spectral ranges. If desired, the layers are combined with filter layers and anti-halation layers and arranged on one or both sides of a support.

In making a multi-color image it is furthermore possible to prepare one or two partial color images according to the present invention and the other partial color images according to another method: For instance, as mentioned above the red and yellow imagesmay be'produced in two layers which are on one side of the support whereas a Prussian blue image may be obtained in a third layer on the other side of the support by the toning process, this third layer advantageously serving for recording a sound track. The

present process is especially suitable for the simultaneous production of sound track and image record when such azo dyestuffs are produced as are capable of being after-treated with a salt of a heavy metal as, for instance, derivatives of salicylic acid suitable for after-chroming. In this case one obtains dyestuffs which contain salts of a heavy metal and show anespecially favorable capability of absorbing the light rays affecting the photo-cells.

It is not necessary that each of the three layers contains both azo dyestuff components already before exposure. For instance, it is possible that only two layers have incorporated therein the two dyestuff components whereas the third layer contains only one azo coupling component. This process is so carried out that the two azo dyestuff images are first produced in the two layers which contain both coupling components whereupon the third layer is bathed in the solution of a diazotizable amine as, for instance, dehydrothiotoluidine-sulfonic acid and after washing ispresent invention. Moreover combinations of dif-' ferent modifications of the present process as well as for other processes are possible whereby numerous ways for reaching the desired color tones are given.

As diazo components all monovalent and bivalent diazotizable amines as, for instance, dehydrothiotoluidine, nitroaniline, benzidine and methyloctadecylstearylanilinesulfonic acid are suitable for the process of the present invention. As azo components all compounds capable of coupling such as phenols and amines are to be mentioned. These compounds may carry radicals effecting fastness to diffusion and watersolubilizing groups. Corresponding with the used diazo or azo components monoor polyazo dyestuffs can be formed.

The dyestuff formers may be rendered fast to diffusion with respect to gelatin in different ways. For instance. molecular groups are disclosed,in Patent 2,179,238, dated November 7, 1939, and which impart to the dyestuif substantive properties with respect to cotton as, for instance, one or several diphenyl radicals, hetero- Ill cylic radicals or stilbene radicals may be introduced into the molecule of the dyestuff former. In U. S. Patents 2,178,612, 2,179,244, 2,186,719, dated November 7, 1939; U. S. Patents 2,186,732, 2,186,733, 2,186,734, 2,186,849, 2,186,851, 2,186,852, dated January 9, 1940, and U. S. Patents 2,280,722, 2,292,575, 2,303,928, 2,307,399, 2,323,590, 2,341,372 and 2,357,393; French Patent 844,637; and U. S. patent applications Ser. Nos. 284,258, filed July 13, 1939; 333,814, filed May 7, 1940, there are disclosed further numerous possibilities of making dyestuif formers fast to diffusion with respect to gelatin. The radicals effecting fastness to diffusion include, for instance, long straight carbon chains, high molecular weight fatty derivatives or long-chain polymers as, for instance, polyethyleneimine. and many polymerizates and mixed polymerizat'es of vinyl derivatives falso together with unsaturated, acids such as maleic acid and crotonic acid). The dyestufi formers made non-diffusing in this way sometimes show the property of producing no real but only colloidal solutions. Also a certain diilicult solubility in aqueous media can prevent the difl'usionfrom the layers. Further diffusionpreventing means are the known precipitating salts.

The non-diffusing dyestuif formers may be incorporatedinto the silver halide emulsions in the presence of wetting or dispersing agents as described in U. 9. Pat. 2,186,717 or in the presence of bile acids or salts thereof as described in U. 8.. Patent 2,324,831.

According to the invention diazo compounds may also be used in the present process which step leads to a further simplification and. possibility of variation. In this instance the photo-- graphic layers whichcontain an azo component capable of coupling and conveniently in a dimcultly diffusing condition are treated in the solution of a diazo compound, if necessary, in the presence of a salt of a heavy metal as, for instance, potassium ferricyanide, copper sulfate and sodium chloride or copper chloride. At the places free from silver an azo dyestuff is formed immediately.-

As diazo solutions there are suitable all solutions of diazotized amines which may contain a stabilizer for increasing the stability thereof. It is, however. also possible to incorporate these diazo compounds into the layers, the only slowly coupling stabilized forms of the diazonium compound and the diazotates being especially suitable. In this case the coupling is accomplished in.

a special bath, ii required, with the addition of a salt of a heavy metal.

The following example illustrates this modification: I

A silver halide emulsion layer which contains 1-phenyl-3-heptadecyl-5 pyrazolone-3' sulfonic acid as a coupling component is exposed, developed. fixed and then treated in cc. of a 1% solution which contains 1 cc. of a 10% copperchloride solution. A yellow dyestuff image is formed at the places free from silver in a short time. As to-the multi-color image a. multi-layer material containing different dyestuff formers in the single layers, for instance, 1-phenyl-3-hepadecyl 5 pyrazolone-3'-sulfonic acid for the yellow image, 2.3-hydroxynaphthoylbenzidide for the purple image and 8-stearyl-aminonaphthol-2.4-disulfonic acid for the blue image is treated after exposure and development of the partial silver images with a suitable diazo solution, for instance, with tetrazoof p nitrobenzene diazoniumchloride tized benzidine or dianisidine whereby the reversed dyestuil images of the original partial silver images are produced.

This modification may also be combined with those already mentioned above in any way in whichcase it is also possible to produce some partial color images by means of a dlazotizing I multi-color negatives or partial sensations and it 1 is possible to work up the photographic material for exposure as well as copying according to the present process. The silver images at first produced may be obtained by simple or reverse development.

' Dyestufi formers especially suitable for the process of the invention further include the folj lowing compounds: diaminobenzoyl compounds of the aminonaphthol-sulfonic acids and -carboxylic acids, naphthylaminosulionic acids and -carboxylic acids, cresotic acids, diaminocarbazoledisulfonic acids, pyrazolones and the ureas of 1 the aminobenzoyl compounds of the mentioned coupling components. Moreover the benzoyl-, benzyland benzilidene compounds of the diam inodiphenyl-ureas, diaminodiphenylthio-ureas,

diaminostilbenes, benzidines and similar compounds which may be substituted at any positions 1 by any radicals capable of .diazotizing or couling, if desired, are of especial importance. 1 Such 1 compounds are, for instance, the urea from p-ami- 1 nobenzoyl-p-aminobenzoyl-I-acid and the urea from p-aminiobenzoyl-p-phenylenediamine sulfonicacid. Furthermore as coupling components the following compounds are suited: aromatic hydroxycarboxylic acidamides as, for instance, hydroxynaphthoic acidarylide, hydroxyanthracenecarboxylic acidarylide, hydroxycarbazolecarboxi ylic acidarylide, hydroxynaphthocarbazolecarbox- 1 ylic acidarylide, amides of the ketocarboxylic acids as, for instance, terephthaloyl-acetic acidanilide,

'; benzoylacetic acidbenzidide and amides of pyrazolenecarboxylic acids or acidamides of aminopy- 5 razolone such as the condensation product from two mols of aminophenylmethylpyrazolone and diphenyldicarboxylic acid,

Moreover couplers heterocyclically substituted l come into question for the present invention such pler containing an acid group and a diilusionpreventing amino group such as a-hydroxynaphthoyldodecylamine-4-sulfonic acid, 2.3-hydroxynaphthoic acldabietinylamide, 2.3-hydroxyanthracenecarboxylic acidoleylamide-w-sulfonic acid e or the esters or amides of color couplers containing hydroxyor amino groups and diffusion-preventing substituents containing at least one acid group as, for instance, 1-stearylamino-8-naphthol-ZA-disulfonic acid, palmi'tylaminophenylmethylpyrazolonesulfonic acid, undecanoylaminobenioylacetylanthranilic acid, 2-laurylamino-8- naphthol-fi-sulfonic acid, moreover compounds as, for instance, acetoacetylamino-4-methyloctadecylaniline-3-sulfonic acid, 4-acetoacetylamino-4- abietinylaminoaniline-3-sulfonic acid, abietinylaminobenzoylanthranilic acid, heptadecylphenylpyrazolonesulfonic acid and -carboxylic acid, condensation products from hydroxycarboxylic acids capable of coupling such as hydroxynaphthoic acid with polymers containing amino groups as, for instance, polyethyleneimine or from polymers containing carboxyl groups such as polymerization products from polymerized vinylalcohol and maleic acid with color couplers containing amino groups such as aminophenylmethylpyrazolone.

We claim:

1. The process of producing only positive azo dye images in a silver halide emulsion containing an azo dye component fast to difiusion and selected from the class consisting of diazotizable amines and azo coupling components, which comprises exposing, developing and fixing said emulsion, incorporating, where'both azo dye components are not in the emulsion,-'said other component in the emulsion, subjecting the emulsion to the action of a solution consisting of an acidified aqueous nitrite solution to cause diazotization of f as arylides of u-naphthindole-2-phenyl -7 -hydroxycarboxylic acid and pyrazolones from 2-paminophenylthiazole. The. heterocyclic radicals maysimultaneously be combined with a further diffusion-preventing radical as, for instance, a

1 diphenyl.

Such compounds are, for instance, 1-

(dehydrothiotoluidyl) -3 (diphenylcarbonylaminophenyl) -5-pyrazolone, 4.4='-diphenyldicarbon- 3 yl-di-3- [p-aminophenyl-l-(p-6'-methyl 2 ben- 5 zoxazolephenyl) -5-pyrazolonel pounds show a certain afiinity-for gelatin owing All these com- I to their special constitution so that they can be 1 both sides of the support.

arranged in the multi-layer process on one or All these compounds which are dyestufi. formthey carry besides the diilusion-preventing radicals such substituents as increase the solubility of the color coupler in aqueous-organic solvents, if

j necessary, in the presence of an alkali or acid. j Such compounds are, for instance, a colorcousaid diazotizable amine and effecting coupling of the diazotized amine and said other component in a coupling bath consisting of an aqueous solution of a water-soluble salt of an alkali and an organic acid.

2. Theprocess as defined in claim 1 wherein said salt of an alkali and an organic acid is sodium acetate.

3. The process of producing only positive azo dye images in a silver halide emulsionlayer containing an azo coupling component fast to diffusion which comprises exposing, developing and fixing said emulsion, treating the emulsion in a solution of a diazotizable amine, subjecting the emulsion to the action of a solution consisting of,

an acidified aqueous nitrite solution to convert the amine into a diazonium compound, and coupling said compound with'said azo coupling component by means of a bath consisting ofan aqueous solution of a water-soluble salt of an alkali and an organic acid to form image only.

{1. The process as defined in claim 3 wherein the salt of an alkali and an organic acid is sodium acetate.

5. The process of producing only positive azo dye images in a silver halide emulsion layer containing an azo coupling component and a diazotizable amine, at least one of said components being fast to diffusion, which comprises exposing, developing and fixing said layer, treating the emulsion with a solution consisting of an acidified aqueous nitrite solution to convert said diazotizable amine into a diazonium compound and coua positive dyestuff pling said azo coupling component with said diazomum compound in a bath consisting of an aqueous solution oi a water-soluble salt of an alkali and an organic acid to produce a positive dyestuil image only.

6. The process of producing only positive azo dye images in a silver halide emulsion layer containing an azo coupling component and a diazotizable amine, at least one of said components being fast to diffusion, which comprises exposing, developing and fixing said layer and treating said layer with a nitrite solution acidified with acetic acid to effect simultaneous diazotization of said amine and coupling thereof with an azo coupling component to form a positive dyestui'f image only.

7. The process of producing only positive azo dye images in a silver halide emulsion layer containing as the am coupling component alphahydroxy-beta-naphthoyl-2 amino 3 palmitylamino-toluidine-5-sulfonic acid, which comprises exposing, developing and fixing said layer, bathing the layer in a bath comprising a solution of dehydrothiotoluidine-4-sultonic acid, treating the layer with a solution consisting oi aqueous sodium nitrite acidified with hydrochloric acid to produce a diazonium compound and then subjecting the layer to the action 01' a bath consisting of an aqueous solution of sodium acetate to effect coupling of said azo coupling component and said diazonium compound to produce a positive dyestui'! image only.

8. The process of producing only positive azo dye images in a silver halide emulsion layer containing as the azo coupling component the sodium salt of alpha-hydroxy-beta-naphthoyl-z-amino- 3-palmityl-amino-toluidine-5-sulionic acid and as the diazotizable amine carbonyl-di-(p-aminobenzoylp -phenylene diamino sulionic acid),

which comprises exposing, developing and fixingsaid layer, treating the layer with a solution consisting of aqueous sodiumnitrite acidified with hydrochloric acid to efiect diazotization oi! said diazotizable amine and then subjecting the layer to the action. of a bath consisting of an aqueous solution of sodium acetate to effect coupling of said azo coupling component and the diazonium compound to produce onlypositive dyestufl images. 1

WILHELM SCHNEIDER. ALFRED FROHLICH.

GUSTAV NEUGEBAUER. 

